Whitespotted Wedgefish

Rhynchobatus djiddensis is a large species of guitarfish in the family Rhinidae. It is restricted to the Red Sea, Persian Gulf, and western Indian Ocean, but was formerly considered more widespread due to confusion with its relatives.

Description

A large fish reaching up to 3.1m long and weighing as much as 227 kg. The colour underneath is white and overall dark greyish or olive above. Large individuals lack the distinct white spots of the closely related white-spotted guitarfish (though some white-spotted guitarfish are essentially unspotted too). It is ovoviviparous, and a female can give birth to litters of up to 10 young.

Taxonomy and range

The giant guitarfish was previously believed to range throughout a large part of the Indo-Pacific, but recent evidence has shown that it, as traditionally defined, actually was a species complex consisting of 4 different species. In addition to the giant guitarfish, this complex includes the white-spotted guitarfish, the broadnose wedgefish and possibly the smoothnose wedgefish. With these as separate species, the giant guitarfish has a relatively restricted range: It is found only in the Red Sea and the tropical western Indian Ocean as far south as South Africa.

Habitat

It is a shy fish, found from 2 m to 50 m depth, inhabiting areas with sandy sea floor. These are generally around coastal reefs or reef flats, but they will sometimes venture into the brackish waters of estuaries.

Diet

The giant guitarfish feeds on bivalves, crabs, lobsters, squid and small fish.

Interaction with human

The giant guitarfish is harmless to humans. It is listed as vulnerable on the IUCN red list as its population are believed to have declined significantly due to unregulated high levels of exploitation for its flesh and fins; the latter for shark fin soup. Its low fecundity and presumed slow growth rate make it highly vulnerable to unsustainable exploitation.